This was a problem for me as my existing images are not square as recommended by Folksy, not having the time to re-photograph this was my solution.
You may have heard of Pixlr.com a free image editor which I use often.
From the homepage click on “Pixlr Editor” then “create new image” in the next box ignore the presets and make the width and height 600 X 600.
This gives you a white background to work on (mine are always white-ish)
Then click on “File” then “Open Image” this should take you to the images stored on you PC, choose the one you want and click “Open”.
This shows you image, move up to Pixlr toolbar and click “Image” then “Image Size”, this shows the height and width of you image.
Ensure “constrain proportions” box is ticked, then change the largest measurement to 600.
This will make the whole image fit the white box when you move it to the white.
In the “Tools” box on the left click the top right “Move Tool”.
Then move over to “Layers” on the right hand side. Left click and drag “background” (your image) to the white box, you image should not overhang the box if the longest measurement is 600.
Then simply click on the image and drag to centre it and save in your file . I save to a seperate file for folksy images.
Have a look at my page to see what the final product looks like, please remember that I am no expert, I’m just trying to get over an issue I was not happy with, image is everything, right?
If this has helped you at all please favourite my page, just to get me started. I only have twelve items listed at the moment but lots more to follow now that I am happy(ish) with my images.